In silver halide photographic materials, it has been frequent practice to color a photographic emulsion layer or other layer in order to absorb light of a specific wavelength region.
For example, when it is necessary to control the spectral composition of light entering a photographic emulsion layer, a colored layer is formed in the photographic light-sensitive material at the side of the photographic emulsion layer farther from the support (i.e., the light entering side of the emulsion layer). Such a colored layer is called a filter layer. When plural photographic emulsion layers exist as a multilayer color photographic material, the filter layer sometimes is disposed between the emulsion layers.
Also, it has been known to form a colored layer between a photographic emulsion layer and a support of a silver halide photographic material or on the support at the opposite side to the emulsion layer-carrying side thereof for preventing the occurrence of halation, that is, the occurrence of fading of images based on the reincidence of light, which was scattered during or after passing through the photographic emulsion layer, reflected at the interface between the emulsion layer and the support or at the surface of the photographic material opposite to the emulsion layer side. Such a colored layer is called an "antihalation layer". In the case of a multilayer color photographic material, the antihalation layer is, sometimes, disposed between the photographic emulsion layers.
Furthermore, in a radiographic light-sensitive material, a colored layer for improving the sharpness is, sometimes, formed as a crossover cut filter for reducing crossover light.
Also, for preventing the reduction of the image sharpness based on the scattering of light in the photographic emulsion layer (this phenomenon is generally called "irradiation"), sometimes the photographic emulsion layer is colored.
These various layers which are colored are usually composed of a hydrophilic colloid and hence for coloring them, a water-soluble dye is usually incorporated in the colored layer. The dye is required to meet the following conditions:
(1) The dye should have an appropriate spectral absorption according to the practical purpose of the material.
(2) The dye should be photochemically inactive. That is, the dye should not give harmful influences, chemically to the performance of silver halide photographic emulsion layers, such as the reduction of sensitivity, fading of latent images formed, and the formation of fog.
(3) The dye should be discolored or dissolved off during photographic processing, so that a harmful color is not left on the photographic light-sensitive material after processing.
Also, when the colored layer is a filter layer or an antihalation layer which is disposed at the photographic emulsion side of a photographic light-sensitive material, it is further required that the dye does not substantially diffuse into other layer(s). This is because if the dye diffuses into other layer(s), not only will the effect of the dye-containing layer as a filter layer or an antihalation layer be reduced but also the dye gives a harmful spectral action to other layer(s).
Various efforts have been made forwards discovering dyes meeting the aforesaid conditions and, in particular, oxonol dyes having two pyrazolone nuclei have a property of being discolored in a developer containing a sulfite and have been used for photographic light-sensitive materials as useful dyes giving less harmful influence on photographic emulsions. For example, there are oxonol dyes having a specific substituent at the 3-position of the pyrazolone nucleus as described in JP-A-50-91627, 50-147712 (corresponding to U.S. Pat. No. 3,989,528), 51-32325 (corresponding to U.S. Pat. No. 4,059,448), 52-34716, 58-143342, and 59-111641. The term "JP-A" as used herein means an "unexamined published Japanese patent application".
Also, there are methods of combining a basic polymer and a dye as described in JP-A-51-32325 and 52-34716.
However, the kinds of dyes capable of selectively dyeing only a specific layer such as a filter layer or an antihalation layer by itself, without substantially the need for a mordant, etc., and which do not leave a harmful color on the photograhic light-sensitive material after photographic processing, as well as dyes which can perform both the selective dyeing and discoloring even in the case of using mordant, are quite few.
Examples of other dyes which are used for the aforesaid purposes are the oxonol dyes having a pyrazolone nucleus or a barbituric acid nucleus described in British Patent Nos. 506,385, 1,177,429, 1,311,884, 1,338,799, 1,385,371, 1,467,214, 1,433,102, and 1,533,516, JP-A-48-85130, 49-11420, 55-161233, 59-38742, and 59-111640, U.S. Pat. Nos. 3,247,127, 3,469,985, and 4,078,933, other oxonol dyes described in U.S. Pat. Nos. 2,533,472 and 3,379,533, British Patent No. 1,278,621, etc., the azo dyes described in British Patent Nos. 575,691, 680,631, 599,623, 786,907, 907,125, and 1,045,609, U.S. Pat. No. 4,255,326, JP-A-59-211043 (corresponding to U.S. Pat. No. 4,559,296), etc., the azomethine dyes described in JP-A-50-100116 and 54-118247 (corresponding to U.S. Pat. No. 4,234,677), British Patent Nos. 2,014,598 and 750,031, etc., the anthraquinone dyes described in U.S. Pat. No. 2,865,752, the arylidene dyes described in U.S. Pat. Nos. 2,538,009, 2,688,541, 2,538,008, British Patent Nos. 584,609 and 1,210,252, JP-A-50-40625, 51-3623, 51-10927, and 54-118247, JP-B-48-3286 (corresponding to U.S. Pat. No. 3,687,670) and 59-37303 (the term "JP-B" as used herein means an "examined published Japanese patent application"), the styryl dyes described in JP-B-28-3082, 44-16594 and 59-28898, the triarylmethane dyes described in British Patent Nos. 446,583 and 1,335,422, JP-A-59-228250, the merocyanine dyes described in British Patent Nos. 1,075,653, 1,153,341, 1,284,730, 1,475,228, 1,542,807, etc., and the cyanine dyes described in U.S. Pat. Nos. 2,843,486, 3,294,539, etc.
In these dyes, the oxonol dyes having two pyrazolone nuclei have a property of being discolored in a developer containing a sulfite, and have been used for photographic light-sensitive materials as useful dyes giving less harmful influences on the photographic emulsions.
However, some of this series of dyes have a fault of spectrally sensitizing the photographic emulsion containing the dye to an unnecessary zone or of reducing the sensitivity thereof. This is considered to be caused by desorbing sensitizing dye(s) although these dyes give less harmful influences on the photographic emulsion itself.
Also, according to quickened or rapid photographic processing which has been practiced recently, some of the aforesaid dyes remain after processing. For solving this problem, it has been proposed to use dyes having a high reactivity with a sulfite ion but in this case, there is a fault that the dyes are insufficient in stability in the photographic emulsion layer, cause a reduction in density with the passage of time, and desired photographic effects cannot be obtained.
On the other hand, when the colored layer is a filter layer or an antihalation layer disposed at the photographic emulsion side of a photographic light-sensitive material, it is usually required that the layer only be selectively colored and other layers are not substantially colored.
For selectively dyeing a specific hydrophilic colloid layer, there are various known methods, but a method of using a hydrophilic polymer including a moiety having static charges opposite to those of a dye ion as a mordant in the hydrophilic colloid layer together with the dye and localizing the dye in the specific layer by the coaction of the polymer and the dye molecule (the coaction is considered to be the attraction by the static charges and a hydrophobic bonding) is most frequently used.
Examples of mordants which are used for this purpose are vinylpyridine polymers and vinylpyridinium cation polymers described in U.S. Pat. Nos. 2,548,664 and 3,148,061 and JP-B-59-31696, vinylimidazolium cation polymers described in U.S. Pat. No. 4,124,386, JP-B-55-29418 (corresponding to U.S. Pat. No. 4,124,386) and JP-A-59-55436, polymer mordants crosslinkable with gelatin, etc., described in U.S. Pat. No. 3,625,694, aqueous sol type mordants described in U.S. Pat. No. 3,958,995 and JP-A-54-115228, mordants having an ammonium structure described in U.S. Pat. Nos. 3,898,088 and 3,958,995, JP-A-49-121523 and 55-33172, reactive mordants capable of forming a covalent bond with a dye described in U.S. Pat. No. 4,168,976, polymers induced from ethylenically unsaturated compounds having a dialkylaminoalkyl ester residue as described in British Patent No. 685,475, the products obtained by the reaction of polyvinyl alkyl ketone and aminoguanidine as described in British Patent No. 850,281, U.S. Pat. No. 2,822,156 and JP-B-49-15820 (corresponding to U.S. Pat. No. 3,706,563), and the polymers induced from 2-methyl-1-vinylimidazole as described in U.S. Pat. No. 3,445,231.
In the case of using the aforesaid method with a polymer mordant, when the layer containing a dye is brought into contact with other hydrophilic colloid layer in wet states, a part of the dye often diffuses from the former layer into the latter layer. The diffusion of the dye not only depends on the chemical structure of the mordant but also depends on the chemical structure of the dye used.
Also, when the aforesaid polymer mordant is used, residual color is liable to remain on the photographic light-sensitive material after photographic processing, in particular, photographic processing with shortened processing time. This is considered to be due to the theory that since the bonding power of the mordant to dye remains to some extent after processing, although the bonding power is considerably weakened in an alkaline solution such as a developer, the dye or a reversible discolored product thereof remain in the layer containing the mordant. Such a difficulty largely depends on the chemical structures of the mordant and the dye.
For overcoming these difficulties, a method of combining a basic polymer and a specific dye is known as described in JP-A-51-32325 and 52-34716. However, it is difficult by such a method to selectively dye only a specific layer without leaving color in the photographic light-sensitive material after photographic processing in a quickened photographic process, which is often employed in practice recently.